1. Field of the Invention
The present invention relates to a chip-type electronic component.
2. Related Background Art
For making electronic apparatus smaller, there has been a high demand for reducing the size of electronic components mounted in electronic apparatus, whereby chip-type electronic components surface-mounted on mounting substrates have been being made smaller in particular. Known as such a kind of chip-type electronic component is one comprising a chip element body including an inner circuit element, and a pair of terminal electrodes positioned at respective end portions of the chip element body and electrically connected to the inner circuit element.
For example, this kind of chip-type electronic component is surface-mounted as the terminal electrodes at both end portions are soldered onto pads of a mounting substrate by way of reflow soldering. These chip-type electronic components have such a small mass as to be easy to move on molten solder in the reflow soldering step. Consequently, there have been cases where the chip-type electronic components rotate in a direction horizontal to a circuit substrate or are erected on the circuit substrate. In particular, when solder cures in a state where a chip-type electronic component is erected (in a so-called tombstone state), electric connections between the chip-type electronic component and pads of the circuit substrate may be broken, whereby the chip-type electronic component may lose its functions on the circuit substrate. Thus, chip-type electronic components having a small outer size incur a fear of causing a mounting failure due to their small mass.
Therefore, in the chip-type electronic component disclosed in Japanese Patent Application Laid-Open No. HEI 10-22164, shoulder portions of outer electrodes (terminal electrodes) traveling from both longitudinal end faces of a ceramic element (chip element body) to its peripheral faces are rounded by a radius of curvature of 60 μm or less while each outer electrode is provided with a protrusion at substantially the center of its portion formed on the end face of the ceramic element such as to form a bump of 5 to 35 μm with respect to its surrounding areas, thereby restraining and preventing the tombstone from occurring. In the chip-type electronic component disclosed in Japanese Patent Application Laid-Open No. 2002-25850, an electrodeless portion unwettable by solder is formed within an end face plane defined by upper and lower side faces and front and rear side faces of the chip component, so as to reduce the moment due to the surface tension of molten solder causing the tombstone, thereby preventing the tombstone from occurring.